Process for removing hydrochloric acid from sugar solutions



July 31, 192s.

- y 1,618;81942 F.KQ cH PROCESS PoR REIovING HYDRocHLoRVIc ACID 'FROMSunnistm-:T10 x.lsnjiy Filed may s, w22/,

Patented daily 3l, i928.

STATES maare rnrrz KOCH, or GENEVA, SWITZERLAND, ASSIGNOR To THE INTERNATIONAL SUGAR AND ALCOHOL COMPANY, LrMITnD, or LONDON, ENGLAND,

PROCESS non REMOVING HYDROCHLORIC ACID FROM SUGAR SOLUTIONS.

Application filed Mayl 9, 1925, Serial No. 29,262, and in Germany may 15, 1924,

This invention relates to a novel and convenient process for removing the hydrochloric acid from glucose or sugar solutions which have been prepared by the treatment of sawdust or Wood-fibre in the known Inanner, and in which the hydrochloric acid is employed for removing fibre and other cellulose constituents.

The object of the present invention 1s to remove this hydrochloric acid completely or practically completely. The solutlonscontaining 75%-100% of hydrochloric acid as compared to sugar must be freed of this acid, so `that this percentage is brought down to 1%-1.5%, as otherwise the treatment of the glucose or sugar for the preparation of cattle foods, pure sugar, alcohol and the like is rendered impossible.

A further object of the invention is to enable the removal of the hydrochloric acid in the most economical manner and wvith simple mechanical means. Another object of the invention is to prevent any conversion. or change in the sugar constituents in the actual sugar `solution due to chemical influences.

According to the present invention,'these objects are attained by introducing the 1mpure vsugar solution in the form of a fine spray to a non-solid and preferably continuallv renewed heat carrier, whereby a practically instantaneous and complete removal of the hydrochloric acid by volatilization is obtained. rlfho non-solid, that is fluid, heat carrier may be in liquid or gaseous form.

The invention 'will be more readily understood from the following description of convenient methods of carrying the saine into eiect in conjunction with the apparatusdiagrammatically illustrated in the drawings.

*igure l is a diagram illustrating one convenient forni, and

Figure 2 isla similar sectional View of a modified apparatus for carrying the invention into effect.

in the drawings similarl parts are designated by the same reference letters.

A closed casing l is provided With an inletpipe 2, to Which a steady stream of hot fluid is supplied. As shown in Figure l, the fluid may be heated oil. The solution to be freed of hydrochloric acid is Supplied, under pressure, to a nozzle or spray 3, opening Within the receptacle l. The take-olf pipe 5 is provided for withdrawing the sugar solution which has been practically freed of hydrochloric acid. The volatilized hydrochloric acid together with any steam that may he generated is drawn oft by the discharge pipe 4.

The fine spray of sugar solution containing hydrochloric acid falls from the spraving device or nozzle 3 in small drops on to the hot surface 6 of the oil 7. It is advisable to keep the surface 6 of the oil 7 in the holder always at the same level. On contacting with the hot oil, the hydrochloric acid in the sugar solution is\instantaneously iapourized Without producing any deleterious effect on the sugar constituents of the solution. The oil takes up the sugar and flows with it through `the pipe 5, and after separation from the sugar solution, the oil is again heated and returned to the holder 1.

In the forni shown in Figure. 2, the hot oil is passed under pressure to the inlet pipe 2, which extends within the holder, and is provided with a rose nozzle 8. By means of this nozzle the oil is passed in a fine film 9 of umbrella shape into the container. Into this ihn of hot oil the nozzle 3 discharges the finely dividedspray of sugar solution. vThis form of the invention has an advantage over that first described in that the oil, during the `heat transference -to the sugar solution, is not itself in Contact' with solid surfaces, which take the ten'iperature of the oil and may `cause excessive heating. ln consequence of this, with this second form, the sugar solution cannot. become candied or the sugar constituentsotherwise altered. rlfhe liquid carrier may, for instance, he vegetable oils. mineral oils, or aromatic hydrocarbons. lt however, also possible to employ some. of the sugar solution itself' as a heat carrier for the purposes olE this invention.

The. heat. carrier may also he in the form of a hot air current or other suitable hot gas. In this case also the hydrochloric acid is practically completely removed when the sugar Solution in finel)Y divided forni cornes in Contact With the heated air current. ln one form of this process, a sugar solution. which has already been treated in any known manner, as for instance by means oi' hot oil, till the percentage of hydrochloric acid is reduced to 10%-157/0, is led in a finely divided spray into a current of air heated to 120-130 degrees C. The spray may be directed against the air current or with it. The process according to this invention can also be used in the case of solutions containing sulphuric acid, acetic acid, formic acid and the like.

The lnew process may also be simplified` and accelerated by adding a suitable quantity of sulphurie acid to the solution to be treated, and by this method the hydrochloric acid may be removed to a greater degree, and a practicall pure solution obtained. This modificatlon of the process may be carried out by adding say two parts of concentrated sulphuric acid to one hundred parts of sugar.v This addition may be made at any time before spraying, thus the sulphuric acid may be added whllst removing the wood fibres, or when vapourizing by means of the hot oil, or it maybe added to the syrup immediately before the latter is sprayed into the hot air current. When thefinished product is to be used for food purposes, the sulphuric acid is subsequently removed by preclpitating it outas a practically insoluble earth-alkaline sulphate, in the known manner. Subsc uent treatment is simple and economical, as y this method the treatment of the sugar is rendered surer and safer, and the content of hydrochloric acid may be reduced to less than 1%.

I wish it to be understood that the imy provided process may be carried out in many different ways, and with different apparatus, without departing from the underlying idea as described above and as set forth in the claims.

I claim:

1. Process for removing hydrochloric acid from sugar solutions consisting in heating a fluid heatin carrier, spraying the sugar solution,l contalning the acid, into said nonsolid heating carrier drawing off the volatilizedh drochloric acid and carrying away the fluidy heating carrier together with the sugar solution.

2. Process for removing hydrochloric acid from sugar solutions consisting in heating a 1i uid heating carrier, spraying the sugar sdlution into said heating carrier drawing oil' the volatilized hydrochloric acid and carrying away the fluid heating carrier together with the sugar solution.

3. Process for removing hydrochloric acid from sugar solutions eonsistlng in using hot oil forming the heating carrier, spraying the sugar solution into the hot oil drawing oli' the volatilized hydrochloric acid and carrying awa the Huid heating carrier together with t 1e sugar solution.

4. Process for removing hydrochloric acid from sugar solutions consisting in heating oil, transforming it into a finely divided state, spraying the sugar solution into said finely divided hot oil and drawing olf the volatilized hydrochloric acid.

5. Process for removing hydrochloric acid from sugar solutions consisting in using a heated liquid and hot air, both serving as 'heating carriers, transforming the heating carriers into a finely divided state, spraying first into the iinely divided heated liquid and then into the hot air, the sugar solution in a nely divided state, drawing olf the volatilized hydrochloric acid and carrying away the liquid heating carrier together with the sugar solution.

6. Process for removing practically all the hydrochloric acid from sugar, glucose and the like solutions consisting in adding a small percentage of sulphuric acid to the said solutions, using in combination first a heated liquid and then hot air, spraying the solution mixed with the sulphuric acid into the spray of the heating carrier respectively, formed by the said heated liquid and hot air, drawing off the volatilized hydrochloric acid and carrying away the heating carriers together with the sugar solution.

7. Process for purifying sugar solutions from hydrochloric acid consisting in heating a liquid, spraying the solution in finely divided form into the said liquid, taking off the hydrochloric acid volatilized by contact with the hot liquid, adding sulphuric acid to said partly purified sugar solution, heatin a current of air, and spraying the mixture o sugar solution and sulphuric acid-into said hot air current.

FRITZ KOCH. 

